Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017168 (gastroesophageal reflux disease)
 11,783 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although more extensive research is required to fully characterize the pathophysiology of the gastrointestinal symptoms in PD, much of the presently available data suggest that the primary PD process is the major factor in the etiology of gut dysfunction in this patient population. This may be mediated by both central and peripheral mechanisms. Involvement of the dorsal motor nucleus of the vagus might produce dysfunction of muscles controlling deglutition and esophageal motility, thereby leading to drooling, dysphagia, and gastroesophageal reflux. The presence of Lewy bodies, the primary neuropathologic finding in the CNS in PD, in the myenteric plexus of both the esophagus and colon suggests that the PD process may also affect the enteric nervous system and contribute to the development of esophageal dysmotility and constipation through this peripheral mechanism. Dopamine receptors have been identified in the lower esophageal sphincter and the esophageal body of animals. If similarly present in humans, involvement of this dopaminergic system could contribute to the development of dysphagia and nausea of PD. Constipation may reflect both peripheral involvement, indicated by Lewy bodies in the colonic myenteric plexus, leading to colonic inertia, and central mechanisms, leading to pelvic floor dysfunction.
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PMID:Gastrointestinal dysfunction in Parkinson's disease: frequency and pathophysiology. 845 Oct 18

Prokinetic agents are currently being investigated as potential therapies for motility disorders of the lower gastrointestinal tract. Cholinergic agonists such as bethanechol are known to improve postoperative ileus but are limited because of side effects. Dopamine antagonists such as domperidone appear to have maximal prokinetic effect in the proximal gastrointestinal tract and are effective for such conditions as gastroparesis and gastroesophageal reflux, but they appear to have little physiologic effect in the colon or in colonic motility disorders. Naloxone, an opioid antagonist, appears to hold promise in patients with irritable bowel syndrome, small intestinal pseudo-obstruction, and constipation. Erythromycin exerts its prokinetic effect by acting as a motilin agonist; it has been used in the treatment of diabetic gastroparesis and appears to improve symptoms of colonic pseudo-obstruction and postoperative ileus. Metoclopramide, a combined cholinergic agonist and dopamine antagonist, is currently used exclusively for proximal motility dysfunction. Cisapride appears to hold the most promise for patients with colonic motility disorders. In patients with postoperative ileus, cisapride is associated with an increased return of bowel function compared with placebo. In patients with chronic constipation, cisapride increases stool frequency and decreases laxative abuse in both adults and children. Hopefully, as an understanding of gastrointestinal motility increases, effective prokinetic agents will be developed that will improve symptoms of patients with large bowel motility disorders and may also help to predict those patients who benefit from surgical management for constipation.
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PMID:Prokinetic agents for lower gastrointestinal motility disorders. 813 79